When did Saul's conversion happen relative to Stephen's stoning?

Stephen was stoned in 36 A.D., and Saul's conversion on the road to Damascus occurred the next year, around 37 A.D. Saul was then at the height of persecuting Jewish believers and had brought about Stephen's stoning before his conversion.

Les explains that there was a seven-year interval between Pentecost and Stephen's stoning, placing the stoning in 36 A.D. Saul was then at the height of persecuting Jewish believers and brought about Stephen's stoning. The next year, Saul's conversion occurred on the road to Damascus, which took him to 40 A.D. when he went to Cilicia. Later, 14 years after 37, he went back to Jerusalem.

Who was responsible for Stephen's stoning, and what was Saul doing at that time?

Saul was at the height of his persecution of Jewish believers and brought about the stoning of Stephen. At that time he was actively persecuting those Jewish believers and was responsible for Stephen's death, which occurred during the seven-year interval after Pentecost, around 36 A.D., before Saul's Damascus road conversion.